Platelet graphite nanofibers for electrochemical sensing and biosensing: the influence of graphene sheet orientation.

Here, we demonstrate that platelet graphite nanofibers (PGNFs) exhibit fast heterogeneous electron-transfer rates for a wide variety of compounds such as FeCl(3), ferrocyanide, dopamine, uric acid, ascorbic acid, and the reduced form of beta-nicotinamide adenine dinucleotide. The electrochemical properties of PGNFs are superior to those of multiwalled carbon nanotubes (MWCNTs) or graphite microparticles (GMPs). Transmission electron microscopy and Raman spectroscopy reveal that this arises from the unique graphene sheet orientation of such platelet nanofibers, which accounts for their unparalleled high ratio of graphene edge planes versus basal planes.